Ophiomyia atriplicis

Ophiomyia atriplicis

The mature gall is ca. 6 mm long and is covered with and hidden by a dense cluster of slightly elongated leaves (Fig. 5A). The leaves of A. polycarpa [host plant] are clustered on axillary buds along the stems, and the adult female inserts a single egg into the stem at the base of a bud. Following eclosion the first instar occupies a small chamber formed in the stem beneath a bud until gall development begins. As the gall develops into its characteristic cone shape, the larva moves into the gall where it feeds and develops in an elongate, central chamber which it excavates with its mouth hooks (Fig. 5B). 

As larval development proceeds, the gall changes from green and succulent to brown and woody. Prior to pupariation, the mature larva scrapes a window near the distal end of the gall wall (Fig. 5C). Pupariation occurs in the gall (Fig. 5C) with the head oriented distally. The adult (Fig. 5D) emerges from the puparium and leaves the gall through the pre-formed emergence window. 

The leaves on empty galls gradually die and turn brown. These empty galls may persist for several months but are no longer present by the following season. Gall development may be initiated anytime from late fall to early spring. 

It is not known how or where O. atriplicis diapauses. Old galls do not support larvae or pupae over the summer, and no galls have been found on other plant species sympatric with A. polycarpa. 

Host: 
Atriplex polycarpa

An interesting new gall-forming Ophiomyia species (Diptera: Agromyzidae) on Atriplex (Chenopodiaceae) in Southern California